Facile synthesis of TiO₂/WO₃ nanocomposites and the electrochemical lithiation/delithiation activity

TiO₂ is an attractive anode material for lithium ion batteries (LIBs). However, the low theoretical capacity and poor conductivity greatly hinder its potential applications. In this work, TiO₂/WO₃ nanocomposites (NCs) are successfully synthesized by a one-step method of DC arc-discharge plasma. It is found that TiO₂ and WO₃ grains are closely combined into bigger particles by chemical/physical adherence, quite different from common connection ways of coating or mechanical mixing. In bigger particles, the combination of WO₃ and TiO₂ grains can reinforce their electrochemical activities, shorten the diffusion distance of Li⁺ ions inside, and effectively avoid side reactions happening at the interface between two phases. Moreover, the WO₃ phase with a theoretical specific capacity of 694 mAh g⁻¹ makes positive contributions to the TiO₂-based materials in the capacity and conductivity. The TiO₂/WO₃ NCs electrode delivers a stable discharge specific capacity of 557.2 mAh g⁻¹ at a current density of 0.1 A g⁻¹ over 100 cycles, which recovers to 664.1 mAh g⁻¹ after suffering from intense current impacts up to 2.0 A g⁻¹.